/Engine/Plugins/Runtime/SmartObjects/Source/SmartObjectsModule/Public/SmartObjectSubsystem.h
Unregisters a callback to be notified if the claimed slot is no longer available and user need to perform cleanup.
void UnregisterSlotInvalidationCallback ( const [FSmartObjectClaimHandle](API\Plugins\SmartObjectsModule\FSmartObjectClaimHandle) & ClaimHandle )